The utility model discloses a sodium storing tube of a sodium-sulfur battery, and belongs to the field of energy storage. The sodium storing tube comprises a core tube and a sodium storing tube hemisphere which is connected with the bottom of the core tube, wherein a first through hole is formed in the bottom surface of the sodium storing tube hemisphere; and a clapboard is arranged between the core tube and the sodium storing tube hemisphere, at least one second through hole is formed in the clapboard, and a plugging component which is elastically connected with the bottom surface of the clapboard and is capable of sealing the first through hole is arranged right above the first through hole. The sodium storing tube has the technical effect that the first through hole in the bottom of the sodium storing tube of the sodium-sulfur battery can be rapidly sealed when a ceramic electrolyte tube of the sodium-sulfur battery cracks.